Glial fibrillary acidic protein (GFAP) in spinal cord of postnatal rat. An immunoperoxidase study in semithin sections.

The presence and distribution of gliofibrillary acidic protein (GFAP) was studied in the postnatal spinal cord of the rat. On birth GFAP can be seen in astrocytic bodies and their processes of ventral columns; perivascular glial membrane was initially seen within white and gray matter; most of the fibers were transversally oriented. There are many mitotic cells, some of them with GFAP in their cytoplasm, while others lack it, thus providing strong evidence to identify two cellular populations as astrocytes and, possibly, oligodendrocytes and to state that neuroglial cells differentiate to astrocytes before myelination gliosis. The glia limitans membrane is continuous from the 5th day onwards and in 17-day-old animals the astrocytic framework of the spinal cord has reached its adult appearance.